The present invention generally relates to a novel and improved construction for achieving strain relief for an optical fiber within a splicer between such optical fibers. More specifically, the present invention relates to an improved construction of an optical fiber strain (or stress) relief for use in a polymer spring fiber optic splicer of the type disclosed in the co-pending U.S. Pat. application of Essert et al., Ser. No. 07/579,127, filed Sep. 6, 1990 still pending.
Optical fibers have become the method of choice in many modern applications. The greater transmission speeds available to users of optical fibers is one attractive benefit of using such fibers. Also, optical fibers provide greater signal transmission clarity, making optical fibers particularly desirable for application in telecommunications networks. However, optical fibers demand certain care in their employment; care that is not as necessary when using older, metallic wire transmission cables.
For instance, because the proper operation of optical fibers depends upon the physical phenomenon of total internal reflection of incident wave fronts, it is desirable that the glass cores of two succeeding optical fibers to be spliced together be aligned with great accuracy and precision. If the cores of the fibers are not so aligned, their misalignment can form an improperly configured reflective interface, resulting in signal distortion and loss. Also, misalignment of the cores may prohibit some signals, or portions thereof, from being completely internally reflected, thereby allowing the wave fronts to escape the transmission line at the splicer.
Even if the optical fiber are properly aligned initially at the splicer, they may become misaligned eventually due to the application of naturally generated forces, or of some other external force. Because optical fibers are often used in a telecommunications network, the splicer between two successive fibers must be able to withstand the forces inherent in that application in order to maintain the alignment of the fiber cores.
Specifically, for example, the optical fibers are subjected to thermal contraction and expansion depending upon the temperature of the ambient environment. Also, the fibers are subjected to forces generated by workmen who service the telecommunications network. The application of these forces can cause misalignment of the fibers, as well as thermal signal loss and torsionally induced failure of the cable and its individual fibers.
In the optical splicer disclosed in the above-referenced co-pending application, compressive or grip-type clamps are applied to the fibers within the splicer. However, to be effective, the clamps had to apply a force to the fibers of sufficient magnitude to resist the above-mentioned forces. Because the structure of the optical fiber is exacting in order to reap the benefits of total internal reflection, the use of the clamps sometimes results in compressive stress signal losses. Such losses have been observed primarily as a result of torsional failures, and primarily in one type of optical fiber, known as the 900 um tight buffered, non-separately strippable fiber. The strain relief of the present invention therefore provides a significant improvement in the grip-type splicer, and is especially desirable for employment with optical fibers similar to the above-described 900 um diameter fibers, which are particularly prone to torsional failure in such a splicer.